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Introduction Acne vulgaris is a common skin condition that affects a significant percentage of adolescents, with scarring being one of its permanent complications. This study aims to compare the efficacy and safety of using botulinum toxin type A (BTA) in combination with cross‐linked and non‐cross‐linked hyaluronic acid (HA) for the treatment of atrophic acne scars. Method Our study is a randomized, double‐blind clinical trial conducted on 16 patients with atrophic acne scars. The patients were randomly assigned to one of two groups: one group received a single session of BTA and crossed link HA combination, while the other group received two sessions of BTA and non‐crossed link HA, 1 month apart. The patients were followed up at 3 and 6 months after baseline to evaluate the number and area of fine and large pores and spots, scar grading, patient satisfaction, and complications. Results The mean age of individuals in both the cross‐linked HA and non‐cross‐linked HA groups was 32.75 ± 4.26 and 31.50 ± 8.48 years, respectively (p = 0.71). In terms of gender, three (37.5%) and seven (87.5%) individuals in the cross‐linked and non‐cross‐linked HA groups were female, respectively (p = 0.11). There were no significant differences in the count and area of fine and large pores and spots between the two groups at baseline and the first follow‐up session. However, in the second follow‐up session, the non‐cross‐linked HA group had significantly better results than the cross‐linked HA group in terms of large pores count and area (p = 0.01). In terms of changes over time, the non‐cross‐linked HA group showed significantly better improvements in the count and area of large pores compared to the cross‐linked HA group (p = 0.03). Additionally, both groups experienced a significant decrease in the count and area of fine pores over time (p = 0.001), but the amount of changes was not statistically significant between the two groups (p = 0.06). Concerning acne grade, initially, 62.5% and 12.5% of cases in the cross‐linked HA and non‐cross‐linked HA groups, respectively, had severe grades. However, in the last session, these percentages significantly decreased to 0% for both groups (p = 0.002 and 0.005, respectively). In terms of treatment complications, none of the patients experienced any adverse effects. Conclusion The study demonstrated that both cross‐linked HA and non‐cross‐linked HA were effective in reducing acne severity and improving the appearance of pores and spots. The treatments had similar effects on fine pores, spots, and overall acne severity. However, non‐cross‐linked HA appeared to have a better result on large pores compared to cross‐linked HA.

Lithium metal batteries show great potential in energy storage because of their high energy density. Nevertheless, building a stable solid electrolyte interphase (SEI) and restraining the dendrite growth are difficult to realize with traditional liquid electrolytes. Solid and gel electrolytes are considered promising candidates to restrain the dendrites growth, while they are still limited by low ionic conductivity and incompatible interphases. Herein, a dual‐salt (LiTFSI‐LiPF6) gel polymer electrolyte (GPE) with 3D cross‐linked polymer network is designed to address these issues. By introducing a dual salt in 3D structure fabricated using an in situ polymerization method, the 3D‐GPE exhibits a high ionic conductivity (0.56 mS cm−1 at room temperature) and builds a robust and conductive SEI on the lithium metal surface. Consequently, the Li metal batteries using 3D‐GPE can markedly reduce the dendrite growth and achieve 87.93% capacity retention after cycling for 300 cycles. This work demonstrates a promising method to design electrolytes for lithium metal batteries. A 3D cross‐linked gel polymer electrolyte shows effective function in uniform lithium deposition compared with traditional liquid electrolytes. The formation of stable interphase effectively restrains lithium dendrite growth, and contributes greatly to lithium cycling performance, achieving 87.93% capacity retention after cycling for 300 cycles at room temperature.

Gels are attractive candidates for drug delivery because they are easily producible while offering sustained and/or controlled drug release through various mechanisms by releasing the therapeutic agent at the site of action or absorption. Gels can be classified based on various characteristics including the nature of solvents used during preparation and the method of cross-linking. The development of novel gel systems for local or systemic drug delivery in a sustained, controlled, and targetable manner has been at the epitome of recent advances in drug delivery systems. Cross-linked gels can be modified by altering their polymer composition and content for pharmaceutical and biomedical applications. These modifications have resulted in the development of stimuli-responsive and functionalized dosage forms that offer many advantages for effective dosing of drugs for Central Nervous System (CNS) conditions. In this review, the literature concerning recent advances in cross-linked gels for drug delivery to the CNS are explored. Injectable and non-injectable formulations intended for the treatment of diseases of the CNS together with the impact of recent advances in cross-linked gels on studies involving CNS drug delivery are discussed.

Cross‐linked thermoset polymeric materials are widely used in various engineering applications due to their excellent mechanical properties, thermal stability, and chemical resistance. Recent research highlights the role of cross‐link density and additives in influencing segmental dynamics and thermomechanical behavior of polymers. This study employs coarse‐grained molecular dynamics (CG‐MD) simulations to explore the thermomechanical and morphologic behaviors of cross‐linked polymers with molecular additives. Specifically, it is systematically investigated how cross‐link density (c) and different additive concentrations (m) affect key glass‐forming characteristics, along with the resulting changes in mechanical and morphologic properties of network materials as they approach their glass transition temperatures (Tg). Relatively weaker interaction between the polymer network and additives can lead to additive aggregation, significantly affecting the morphology and Tg as the m increases. Increasing c leads to an increase in both Tg and fragility while increasing m decreases them. The simulation reveals that both c and m moderately influence the mechanical properties (i.e., shear and tensile modulus) of cross‐linked polymers with additives. This study provides valuable insights into how cross‐link density and additive concentrations influence glass‐forming and morphological behaviors, offering a molecular design strategy for developing advanced cross‐linked thermosets. The thermomechanical and morphological behaviors of cross‐linked polymers with molecular additives are investigated using coarse‐grained molecular dynamics (CG‐MD) simulations. The influence of cross‐link density and additive concentration on glass transition temperature, fragility, and mechanical properties is systematically explored. Findings highlight that additive aggregation alters morphology and Tg, while higher cross‐link density increases Tg and fragility. This work provides molecular insights into designing advanced thermoset polymers with tailored properties for engineering applications.

Vulcanisation is a process of transforming a plastic rubber compound into a highly elastic product by forming a three-dimensional cross-linked network structure in the rubber matrix. Many systems have been developed to vulcanise rubber compounds, among which sulphur and peroxide curing systems remain the most desirable. The application of sulphur systems leads to the forming of sulphidic cross-links between elastomer chains, while carbon–carbon bonds are formed in peroxidecuring. Both vulcanisation systems provide certain benefits to the cross-linked rubber articles, but also some disadvantages. The present work seeks to provide an overview on both vulcanisation systems; their composition, possibilities of their application, reaction mechanisms, structure of the cross-links formed and the main feature of the final cross-linked materials — vulcanisates.

Nano titanium dioxide (TiO2) with photocatalytic activity was firstly modified by diethanolamine, and it was then doped with broad spectrum antibacterial silver (Ag) by in situ method. Further, both Ag doped TiO2-chitosan (STC) and TiO2-chitosan (TC) composites were prepared by the inverse emulsion cross-linking reaction. The antibacterial activities of STC composites were studied and their antibacterial mechanisms under visible light were investigated. The results show that in situ doping and inverse emulsion method led to good dispersion of Ag and TiO2 nanoparticles on the cross-linked chitosan microsphere. The STC with regular particle size of 1–10 μm exhibited excellent antibacterial activity against E. coli, P. aeruginosa and S. aureus under visible light. It is believed that STC with particle size of 1–10 μm has large specific surface area to contact with bacterial cell wall. The increased antibacterial activity was attributed to the enhancement of both electron-hole separations at the surface of nano-TiO2 by the silver ions under the visible light, and the synergetic and sustained release of strong oxidizing hydroxyl radicals of nano-TiO2, together with silver ions against bacteria. Thus, STC composites have great potential applications as antibacterial agents in the water treatment field.

In solid mechanics, data-driven approaches are widely considered as the new paradigm that can overcome the classic problems of constitutive models such as limiting hypothesis, complexity, and accuracy. However, the implementation of machine-learned approaches in material modeling has been modest due to the high-dimensionality of the data space, the significant size of missing data, and limited convergence. This work proposes a framework to hire concepts from polymer science, statistical physics, and continuum mechanics to provide super-constrained machine-learning techniques of reduced-order to partly overcome the existing difficulties. Using a sequential order-reduction, we have simplified the 3D stress–strain tensor mapping problem into a limited number of super-constrained 1D mapping problems. Next, we introduce an assembly of multiple replicated neural network learning agents (L-agents) to systematically classify those mapping problems into a few categories, each of which were described by a distinct agent type. By capturing all loading modes through a simplified set of dispersed experimental data, the proposed hybrid assembly of L-agents provides a new generation of machine-learned approaches that simply outperform most constitutive laws in training speed, and accuracy even in complicated loading scenarios. Interestingly, the physics-based nature of the proposed model avoids the low interpretability of conventional machine-learned models.

Skin scarring can result from burns, injuries, stretch marks and acne, leading to cosmetic and functional difficulties. Treatments for burn scars encompass a range of options, such as lasers, corticosteroid injections, surgery and regenerative techniques such as platelet‐rich plasma (PRP). Hyaluronic acid‐based products offer skin hydration and shield against aging effects. A study is being conducted to evaluate how effective PRP injection, hyaluronic acid and their combination improve burn scars and their effects on quality of life and potential disabilities. In our study, PRP and non‐cross‐linked hyaluronic acid treatments were compared in 10 individuals with burn scars between 2022 and 2023. Patients received CO2 fractional laser treatment followed by injections in scar areas. Evaluations included the Vancouver scar scale (VSS), biometric assessments, ultrasounds and satisfaction ratings. Two therapy sessions were conducted at 1‐month interval, and assessments were done before treatment, 1 month after the first session, and 3 months after the first session. Biometric assessments showed significant improvements in various parameters (tewametry, corneometry, erythema index, melanin index, cutometry, thickness and density) in the intervention groups compared to the placebo group (p <0.05). PRP‐non‐cross‐linked hyaluronic acid, PRP and non‐cross‐linked hyaluronic acid treatments exhibited the best clinical responses with significant differences between groups (p <0.05). Dermal thickness did not show significant improvement during treatment sessions, and changes among subjects were not significantly different. The colorimetry parameter improved in all groups except the placebo group, with no significant difference between intervention groups. The VSS significantly decreased in all treatment groups except the placebo group. PRP, non‐cross‐linked hyaluronic acid and especially the combination of these two treatment options are very effective in treating burn scars.

Rheumatoid arthritis, a major joint pain problem in the elderly, has led to increased research on its causes and treatment. This study aims to develop an implant formulation of Ibuprofen using plain drug, cross-linked chitosan, and chitosan as release retardant matrix. The implants were evaluated for optimal formulation to achieve maximum sustained effect over specific days. The drug and polymer were found to be compatible, with drug content ranging from 91.67-99.62%, diameter ranging from 7.15-7.40mm, hardness ranging from 2.6-3.4kg/cm3, thickness ranging from 2.22-2.59mm, and weight ranging from 93.2-101.2mg resp. The formulation A4 and A5 showed sustained action compared to other formulations of both cross-linked and non-cross-linked batches. The study concludes that chitosan inclusion changes the drug's release profile, resulting in sustained action on the prepared implants.